package com.yueke.gemini.utils;

import java.security.MessageDigest;

/**
 * 微信公众平台(JAVA) SDK
 * SHA1算法
 * http://www.cnblogs.com/accumulater/p/6151953.html?utm_source=itdadao&utm_medium=referral
 * Created by admin on 2017/5/24.
 */
public final class SHA1 {

    private static final char[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5',
                           '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

    /**
     * Takes the raw bytes from the digest and formats them correct.
     *
     * @param bytes the raw bytes from the digest.
     * @return the formatted bytes.
     */
    private static String getFormattedText(byte[] bytes) {
        int len = bytes.length;
        StringBuilder buf = new StringBuilder(len * 2);
        // 把密文转换成十六进制的字符串形式
        for (int j = 0; j < len; j++) {
        buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
        buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
        }
        return buf.toString();
        }

        public static String encode(String str) {
        if (str == null) {
            return null;
        }
        try {
            MessageDigest messageDigest = MessageDigest.getInstance("SHA1");
            messageDigest.update(str.getBytes());
        return getFormattedText(messageDigest.digest());
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        }
}
